Styphnate compound and priming composition thereof



STYPHNATE COMPOUND AND PRIMING COMPOSITION THEREOF Joseph F. Kenney, Huntington, Conn., asssignor to Remington Arms Company, Inc., Bridgeport, Conn., a corporation of Delaware No Drawing. Application August 2, 1952, Serial No. 302,418

4 Claims. (Cl. 52-4) This invention relates to a new composition of mat- 15 ter which is of an explosive character and highly useful as an ingredient of deflagrating composrtions, particularly priming mixtures for small arms ammunit on.

The composition is a complex of two salts of styphnic acid and a salt of hypophosphorous acid. n e 20 method for the preparation of a laboratory quantity is as follows:

10 grams of styphnic acid is suspended in about 100 cc. of water at 40 C. To this suspension there rs added, under agitation, about 10 cc. of 8-n ormal potassium hydroxide and about grams of sodium hypophosphite. The temperature is then raised to between C. and 80 C., preferably about 75 C., and a solution of 25 grams of lead nitrate in 50 cc. of water is added dropwise, with stirring. The addition of the lead n1- trate solution is completed in about 30 mmutes. Stirring is continued for from 30 to 45 minutes, the temperature being maintained between 70 C. and 75 C. The precipitate is in the form of thin plates, the faces of which are typically elongated parallelograms, the ends of such parallelograms being parallel and inclined to a perpendicular to the parallel sides at an angle of about 20. The length of an average crystal is about three times its width, and the crystals are a brown color. Analysis shows that they contain the hypophosphite radical, about 2.4% potassium, about 39.9% lead, and about 2.2% phosphorus, substantially conforming to the structural formula N02 NO:

N z 2 N02 The product, which will be called potassium styphnate-1ead styphnate-lead hypophosphite, is sensitive to percussion and moderately sensitive to static electricity. In admixture with 10% glass and in an unanviled primer cup its average firing point under the impact of a falling 2-oz. weight is 1.95" and the standard variation in sensitivity is 1.3". In a static test, 100% fires are secured by the discharge of a BOO inf. condenser at 500 volts and fires secured by the discharge of a 300 condenser at 200 volts. Its explosion point on a temperature gradient bar is above 250 C. It has an apparent density of 1.035 grams per cc.

Another method of preparing potassium styphnatelead styphnate-lead hypophosphite is as follows:

To a suspension of 10 grams of styphnic acid in 100 cc. of water at a convenient temperature, say 40 C., there is added, with stirring, about l.64 grams of magnesium oxide and subsequently 5 to 10 grams of potassium nitrate and 5 grams of sodium hypophosphite. Stirring is continued for about 10 minutes. The temperature is then raised to form 60 C. to 80 C., preferably 75 C., and a solution of grams of lead nitrate in 50 cc. of water is added dropwise over a period of about minutes. As before, stirring is continued for from 30 to minutes, the temperature being maintained between 70 C. and 75 C. The precipitate is substantially identical with that resulting from the method first above described.

In admixture with an initiating ex losive and an oxidrzer, the new composition 00 tutes an excellent 30,7 Patented Feb. #22, 1955 primer for small arms ammunition, particularly of the rimfire type. It has the extraordinary property of enabling the production of a rimfire priming mixture withthe use of the composition of the present invention without glass or other abrasive and without the use of any separate fuel ingredient. Production is thus simplified by the elimination of a plurality of ingredients heretofore deemed necessary. Typical priming mixtures are as follows:

Range, Preferred, percent percent Normal Lead styphnate 0 to 50 36 Tetrazene 1 to 5 4 Potassium Styiphnate-Lead Btyphna ad Hypophosph 2 to 50 10 Barium Nitrate 40 to 66 This composition has an average sensitivity to the impact of a falling 2-oz. weight of 6.42", and a sensitivity variation of 0.82". The average sensitivity is comparable with that of mixtures in common commercial use, and the sensitivity variation is substantially less. The mixture is also very stable under moist storage. In a standard barrel time test, the freshly prepared mixture gave an average barrel time of 2.58 milliseconds, with a variation of 0.179 millisecond. After three days storage, at 120 F., 90% R. H., the average barrel time was 2.83 milliseconds, and the variation 0.215 millisecond. Aftentwenty-six days of such storage, the average barrel time was 3.04 milliseconds, and the variation 3.41 milliseconds. A commercial mixture used as a standard of comparison had, when fresh, comparable barrel time and variation, but after three days storage a substantially greater barrel time and variation, while after twenty-six days storage it misfired completely.

This application is a continuation-in-part of applicants 'co-pending application, Serial No. 242,037, filed August 15, 1951, now abandoned.

What is claimed is:

1. The composition of matter potassium styphnatelead styphnate-lead hypophosphite.

2. A deflagrating composition comprising as its essential ingredients the complex potassium styphnateleagstyphnatedead hypophosphite, an explosive, and an 0X1 lzer.

3. A priming mixture for small arms ammunition consisting essentially of Per cent Normal lead styphnate Oto 50 Tetrazene Ito 5 Potassium styphnate-lead styphnate-lead hypophosphite 2to 50 Barium nitrate 40 to 4. A" priming mixture for small arms ammunition FOREIGN PATENTS 582,976 Great Britain Dec. 4, 1946 

1. THE COMPOSITION OF MATTER POTASSIUM STYPHNATE LEAD STYPHNATE LEAD HYPOPHOSPHITE.
 2. A DEFLAGRATING COMPOSITION COMPRISING AS ITS ESSENTIAL INGREDIENTS THE COMPLEX POTASSIUM STYPHNATE LEAD STYPHNATE LEAD HYPOPHOSPHITE, AN EXPLOSIVE, AND AN OXIDIZER. 